In an apparatus as described in European Patent application No. 206,374, the workpieces are wrapped in a jacket of paper to which the workpieces are conveyed over one or two conveying troughs from associated counters. The apparatus has a wrapping station laterally adjoining the conveying troughs, a mechanism for transferring the stack or stacks to the wrapping station and a folding mechanism for closing the ends of the jacket. It also includes a mechanism for bringing and applying adhesive closing strips to the folded ends of the jacket.
A table is movable transversely to the longitudinal direction of the stack for receiving and transferring a single stack is provided to which the stacks of covers are transferred from a conveyor by a carriage-mounted and guided gripping and clamping device. The movable table with the cover stack on it is moved toward a portion of the wrapping paper which is hanging down and a fixed guide table of the apparatus and pushed on the fixed guide table of the apparatus to form a partially wrapped stack in the paper jacket.
A piece of the paper for jacketing the stack is cut away from the paper sheet and placed around the stack with the help of a pressing member to form the paper jacket. Then an end portion of the wrapped papaer can be provided with an adhesive strip.
The stacks thus wrapped are conveyed further transverse to their longitudinal direction by the following stack being pushed into the winding station and reach folding elements which engage its ends to fold the projecting portion of the paper jacket to form a cross-like end piece after thrusting the stack between locally fixed pressing rails running transversely to the longitudinal direction of the stacks in one step.
The pressing rails simultaneously form guides for the adhesive closing strips on their ends facing the ends of the stacks. The adhesive closing strip is glued on the ends of the stacks and cut through with a knife blade between adjacent stacks.
The known apparatus, because of the laterally movable table and the laterally loaded stationary guide table for receiving of the stacks thrust transversely to their longitudinal direction, is comparatively wide so that because of spatial requirements putting the stack in place during the conveying process, particularly for metal covers, leads to considerable difficulties.
Further considerable efforts or expenses are required for the transfer of the stacks in the wrapping station and the lateral sliding of the movable table.
With covers with a flanged edge because of wear of the flanged material and/or small differences in the deformability of the material, variations in the thickness and/or in the width of the cover edges occur so that with the usual number of covers in each stack length, differences in the stack of up to a few centimeters can occur.
In the known apparatus the rails and/or folding elements provided for the folding process of the protruding ends of the jacket and for the application of the adhesive closing strips must be arranged so that with the length of the stack a maximum the stacks can still be thrust between the rails and folding elements engaging their ends. Thus stacks with different covers pressed together and with jackets engaging about the covers with different tightness result. These differences become disadvantageously noticeable in the inevitable later removal of the covers from the jacket for further processing.
Particularly, with aluminum covers the stacks of the counted covers are so different in length that one of the rails and the associated folding elements cannot be used. When the second end cannot be automatically folded is necessary to fold that end of the protruding paper manually to form the jacket.